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"moly" is short for Molybdenum [disulfide] a compound that is mined out of the earth and is mostly used for lubrication.
there is a line of grease that have a small percentage of moly in them usually for extreme pressure use like the fifth wheel of a tractor trailer
if a grease is dark gray in color and really tacky, it usually has moly in it about 3 percent is common

several years ago, and I don't know alot about this, but someone got the idea to coat bullets with moly.

if you google it, they are like satin sheets, you either love em or hate em

after the moly gets hot, it changes and can cause really bad corrosion in gun barrels.
this is provided there is enough humidity in the air where you live

I personally don't use them and wouldn't but that is just my opinion;)
 

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Massback, I can tell you a little something from my personal experience. I obtained thousands .224 moly coated bullets in a recent deal. They are multiple grains. I loaded 50 of them for the first time last weekend. What I found is the bullet slips in the case with a moderate amount of pressure. Although I don't crimp my .224 bullets, I am going to have to impart a slight taper crimp on the rounds I've loaded. I've never fired any rounds that were moly coated so I can't answer to that, but since I have so many bullets that are I have decided to reload them and see how it goes.

I'll keep you posted,

kevinh
 

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I will share with you guys what I know to be the truth about moly after several years and hundreds of rounds fired in many calibres. The pros are you can if done right get faster loads with less pressure and far more shots without fouling your bore and if the barrel is in good condition to start with less varition in speeds. The cons are far fewer if you follow a few basic items pertaining to gun care that you should be doing anyway. As stated earlier a moly treated bore can gather rust if improperly stored. Less cleaning doesnt mean no cleaning. You should be cleaning your guns anyway but with moly you may be inviting the gremlins to visit you.
First thing to avoid is excess mloy. More is not better. Most factory bullets arrive with so much moly you can rub your fingers accross them and get the stuff on your fingers. Wipe them down real well with a soft cloth or paper towels. This is the leading cause of the build up in the barrels the nay sayers refer to.
Moly is slicker than greased owl poop. This creates a special situation when loading and shooting moly coated bullets. Neck tension needs special attention as stated by another poster. This can be remedied by use of either a taper or factory crimp die offered by Lee. I swear by one or both if you do or do not use moly. It uniforms start pressure when the round is fired.
Pressure now being the word changes as well as the bullet moves more freely down the bore. What this means is in order to reach published speeds and pressures listed in your load manuals you will need to increase the powder. This is the kinda sorta bad part on moly. My tests found between 1 and a half to 2% more powder was required to reach the published load data. I used a chrony throughout all my testing and measured all my cases at and above the web as well as monitored primer changes and never had issues in the few times I pushed the max load envelope for the best performance. Do not take this to mean you should not do the same.
My personal overview of moly is that it does indeed have its place. Do you need to moly everything ? I say NO . I cant imagine my .223 varmit rifle not having moly when on a 500 round plus sage rat hunt. My old 96 Sweede and circa 1934 Mosin Nagant with barrels nearly 30 inches long love moly too. My .243 which launches 75 grain pills at 3,300 fps loves moly too. The original throat shot out of it at near 500 rounds. This isnt happening with moly. If you shoot hyper velocity ammo on a frequent basis then moly makes good sense. Longer shot strings between cleanings, less frictional heat and less barrel errosion and in over 75% of my tests better shot grouping.
Cleaning the bore periodically is easier for me. I use a mild solvent like Hoppes #9 on a patch , let set a few and use a nylon brush for 10 full passes and dry patch till clean after about 40 rounds in my .223 or when I am done. If indeed I am completely done I dampen a patch lightly with eiher Tri-Flo or Rem Oil to keep any possibility of rust getting to the bore while stored. There are others that work well too but these are my 2. I have never had the buildup issue others speak of and I dont believe in the Boogie Man either. Until I see either one I will remain a non believer. Dont clean and store your guns properly and you just may be the Boogie Man that kills your guns,,,:D

10 Spot

***** Sorry for the format, it was nice paragraphs when I typed it *****
 

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Thanks for the reassurance, 10 spot. I probably spend more time cleaning my rifle than shooting it. It's just who I am. I clean it after every shooting breaking it down to it's smallest parts (disassemble the BCG, buffer and spring, etc.). I use the same methods and solvents/Rem Oil as you. So, I shouldn't worry excessively about degradation of the barrel?

Also, I don't have a Lee Factory Crimp die. I'm just using the Redding bullet seater/crimp die to place a taper crimp ever so slight. Think I'm good to go with that?

kevinh
 

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Moly is short for Molybdenum Disulfide. It is a dry film lubricant commonly used in racing oils and wheelbearing grease. It is also alloyed with steel and chromium to create Chromoly steel, which is used in racecar chassis. By itself it is an excellent friction reducer. When applied to projectiles it acts as a buffer between the bore and the bullet creating less friction, thus lower pressure and more velocity. It does have its drawbacks though. Generally it is very difficult to remove from the bore of your rifle, though I do not know why youd ever need to remove it. I have used them intermittently alongside regular jacketed bullets and have had no issues in more than a decade of constant shooting. if you can get them for a decent price, by all means use them.
 

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OK, now I'm a little confused. Understanding all the properties of moly coating, does it NEED to be removed from barrels because of the potential rust problems or leave the coating in the barrel to protect it from continued wear due to friction? Or, am I splitting hairs here?

kevinh
 

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OK, now I'm a little confused. Understanding all the properties of moly coating, does it NEED to be removed from barrels because of the potential rust problems or leave the coating in the barrel to protect it from continued wear due to friction? Or, am I splitting hairs here?

kevinh
That is exactly the big debate about moly (or "the other disulfide"... Tungsten Disulfide) coatings. You can spend days reading info on the subject...be in on the net or in books and gun rags...and still come away confused on the subject.

Yes, a moly coating will reduce friction and wear on the rifling.
Yes, it can be a stinker to clean from a bore if you get an excessive buildup (many times caused by home-coated bullets with too much lube on them as I understand).
Yes, the heat & pressure inside the barrel from the shooting process will convert some of the disulfide coating into a sulfite compund which can react with moisture in the air and cause corrosion. Just keep the bore oiled between sessions and this isn't a problem.

I personally haven't done much of anything with moly bullets so I would have to say that 10 Spot's experience holds more validity than any info I can give.
I've shot a few moly bullets, but haven't done any serious load development with them.

I bought a pair of .22-250 prairie dog rifles from a local fellow that had a steady diet of moly bullets. Both needed a SERIOUS cleaning when I bought them. the guy had 500-1000 rounds through each and they just wouldn't group anymore. He though the throats were gone, but after much scrubbing (copper and moly fouling) they both came back to shooting sub-MOA groups.
The stainless barreled Rem700 is just fine.
The blued Savage does have very fine pitting in the bore, but doesn't affect groups beyond my satisfaction. It's just a stinker to get the copper fouling out of that barrel now. I can't say for sure that pitting was caused by sulfite corrosion....

I think if I did try another non-friction coating it would be HBN, because when it breaks down it won't form a corrosive sulfite.
 

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Kevinh,

You should be able to get enough crimp with the taper die but I myself used the FCD die with no issues. Dont reccomend neck size only dies unless they have tension equal to what you would get from a full length sizing die. If using Lee neck sizer dies they run weak but you can order smaller mandrels for them as I did for my .264 win mag.

Once moly is used it will leave a lite film in the bore. It can and will shoot out over a time if moly bullets are not used continualy . The point that is being made is not to allow an excessive build up,,, hence periodic solvent with some lite brush and patch work. The excess moly on bullets can come from both commercial as well as home treated bullets. I have a remedy for this as well. I prefer my own treated bullets and this is my method. I have a spare bowl for my vibratory tumbler dedicated to moly. When I treat my bullets I have appx 3 of the large packs of copper BBs' that I place in the bowl with appx 200 bullets, add the minimal 1/8 teaspoon of powdered moly from midway as the tumbler is running spreading ( sprinkling ) slowly over the BBs' and let them run for a good hour . The BBs' tend to peen the moly into the jackets nicely. I then remove the bullets from the tumbler and roll them briskly inside of an old rag such as a T-shirt until the rag comes up clean. I do this with factory coated bullets as well. This stops the BS of the buildup as long as you do some intermediate solvent and brush work during prolonged shooting sessions as you would to keep copper fouling down but not nearly as often with moly coated bullets. Again be mindful to clean and oil patch the bore at the end of your shooting session before storage.

PS,
If you follow my home method to moly coat bullets you also get the worlds fastest BBs' . My Crossman 760 powermaster is a terror !!!

10 Spot
 

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10 spot, that is a great idea. The guy I got the bullets from had a couple extra bowls that came in the deal. He had one labeled "moly only". Since there were many different grains of bullets, he stored each weight in a zip lock bag and kept them all in that same "moly only" bowl. I don't know if his method of coating included BB's or not, but that is an excellent idea that I will incorporate. Although, I have so many moly coated bullets that alzheimer's will kick in by the time I need to coat more bullets.

Thanks for the advice,

kevinh.

PS, would it benefit to moly coat handgun bullets also?
 

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Sorry it took so long to get back to you Kevin. I dont moly coat my handgun bullets as I generally shoot about 90% cast bullets and have a bullet lube that takes care of business leaving my bores nice and shiney. What I do though with my revolvers is to buff the forcing cones of the barrels with moly. This is because the lube on the bullets does not start to dissipate in the area of the forcing cone just when they seal themselves in the barrel. This stops the minor amount of leading that can occur in that area as well as keeps powder fouling and carbon buildup at a minimum also. My revolvers require very minimal cleanup which I dearly love.

10 Spot
 
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